Mattress overlay



FIG. 1 is a top plan view of a mattress overlay showing a portion of the top surface with our new design, wherein the pattern of the design continues throughout the entire top surface;

FIG. 2 is a right side elevational view of our design, which is partially broken away to show the recesses formed in the top surface, with the left side elevational view being identical thereto;

FIG. 3 is a front end view of the mattress overlay, with the rear end view being identical thereto; and,

FIG. 4 is a bottom plan view of the mattress overlay. 

The ornamental design for a mattress overlay, as shown and described. 